Method of winding a loop containing coil



g 2, 1966 F. H. CARMAN ETAL 3,263,309

METHOD OF WINDiNG A LOOP CONTAINING COIL Filed April 20, 1959 2 Sheets-Sheet 1 I I {g I, N. g C) I X a Q I Q- u.| --a q INVENTORS FRANK H. CABNAN JAMES R. VANDE SANDE BY {M mun ATTORNEY Aug. 2, 1966 F. H. CARMAN ETAL 3,263,309

METHOD OF WINDING A LOOP CONTAINING COIL Filfid April 20, 1959 2 Sheets-Sheet 2 A //0 me i -25 coumifi /z u m4 INVENTORS FRANK H. CARHAN C? 4 JAMES B. VANDE SANDE /w! Km THEIR ATTORNEY United States Patent 3,263,309 METHOD OF WINDING A LOOP CONTAINING COIL Frank H. Carman and James R. Vande Sande, Rochester, N.Y., assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed Apr. 20, 1959, Ser. No. 807,395 2 Claims. (Cl. 29-15557) This invention pertains to coils for electrical apparatus, and particularly to a center tapped coil and a method of making the same.

In the manufacture of split series reversible motors having only one wound pole, a center tapped coil can conveniently be used. A motor of this type is disclosed in copending application Serial No. 680,238 filed August 26, 1957, now U. S. Patent No. 3,045,137, in the name of Simmons et a1. and assigned to the ass-ignee of this invention. The present invention relates to a unique center tapped field coil wherein a loop is formed in an intermediate turn of the coil in such a manner that the succeeding turns of wire securely retain the loop in assembled relation with the coil. In addition, the present invention contemplates a unique method of winding center tapped coils from a continuous length of wire by withdrawing a loop from an intermediate turn near the center of the coil. Accordingly, among our objects are the provision of an improved center tapped coil construction; the further provision of a coil construction having a looped intermediate turn which is securely held in assembled relation by successive overlying turns; the further provision of a method of making a tapped coil from a continuous length of wire; and the still further provision of the method of Winding a coil wherein a loop is withdrawn from an intermediate turn.

The aforementioned and other objects are accomplished in the present invention by winding substantially half of the total number of turns on a bobbin, withdrawing a loop from an intermediate turn, and then winding the remaining turns on the bobbin from a continuous length of wire. Specifically, the completed coil construction includes a bobbin having a loop withdrawn from an in termediate turn of a predetermined number of turns wound thereon from a continuous length of insulated wire. The ends of the continuous length of wire extend from one side of the bobbin. These ends can be twisted together, bared of insulation and electrically connected so as to form a common ground connection for the two portions of the center tapped coil. The loop of the center turn is severed and the bared ends thereof areeleotrically connected to a terminal assembly.

In winding the tapped coil, a bobbin is placed on a stationary winding head. The end of the wire from the coil, constituting a start lead, is clamped in a fixture. A power operated flyer type winding arm is rotated about the winding head and bobbin and simultaneously reciprocated to evenly distribute the turns on the bobbin. After substantially half of the total number of turns are wound on the bob-bin, a hook is extended between the winding arm and the bobbin so that a portion of the next turn is wound about the hook. The hook is automatically moved out of the path of the succeeding turns by the wire tension so that the remaining turns are again evenly distributed on the bobbin by the flyer type winding arm. Movement of the winding arm is automatically arrested after a predetermined number of turns are wound on the bobbin. The wound coil is thereafter removed from the winding head and the end lead is severed.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying dirawings,

Patented August 2, 1966 wherein a preferred embodiment of the present invention is clearlyshown.

In the drawings:

IFIGURE 1 is a schematic view, partly in section and ,partly in elevation, illustrating apparatus for carrying out the coil winding method of this invention.

FIGURE 2 is a fragmentary view, partly in section and partly in elevation, illustrating the manner in which a loop is withdrawn from an intermediate turn of the coil during the winding operation.

BIGURE 3 is a schematic diagram of an electrical circuit for controlling the winding apparatus used in carrying out the coil winding method of this invention.

FIGURE 4 is a perspective view of a center tapped coil constructed according to this invention.

FIGURE 5 is a plan view in elevation of the completed coil construction with a terminal block attached thereto.

With particular reference to FIGURE 1, apparatus for carrying out the coil winding method of this invention is schematically shown including an electric motor 10 having a shaft 12 drivingly connected with the input side of an electrically operated clutch 13. The output side of the clutch 13 is drivingly connected to a gear reduction unit 14 having two output shafts 16 and 18. The output shaft 16 has a gear 20 connected thereto meshing with a gear 22. The gear 22 is'drivingly connected to an upstanding hollow shaft 24 supported by bearings 26. The gear 22 also meshes with a gear 27 which drives a counter 28 that can be selectively adjusted to determine the number of turns to be wound on the coil.

A reciprocable shuttle 30 has a straight spline connec- ;'tion, as indicated by numeral 32, with the shaft 24 so as to rotate therewith while being capable of axial move ment relative thereto. The shuttle 30 includes a collar section 34 which receives the end of a yoke 36 formed on one end of a bellcrank 38 having an intermediate fixed pivot 40. The other end of the bellcrank 38 carries a cam follower roller 42 that is received by a groove 44 in a rotatable cam 46. The cam 46 is drivingly connected to a shaft 47 driven by a bevel gear 48 that meshes with a bevel gear 50 driven by the shaft 18. The cam 46 is driven in timed relation with rotation of the shaft 24 so as to reciprocate the shuttle 30, and thereby evenly distribute the turns of wire on the coil bobbin in a manner well known in the art.

A winding arm 52 is attached to the shuttle 30, the winding arm supporting a pair of pulleys 54 and 56 and having an upstanding eyelet 58. A continuous length of insulated wire 60 is unwound from a reel 62, passed between a plurality of tensioning rollers 64 and over the periphery of a guide pulley 66. The wire 60 extends through the hollow shaft 24, over the guide pulley 5'4 and around the guide pulley 56. The wire 60 also extends through the eyelet 58.

A bobbin 68 is supported on a two-part winding head comprising a stationary lower part 70 and a movable upper part 72. The bobbin 68 is composed of insulating material and includes a hollow core 69 having a flange 71 at each end. The upper part 72 of the winding head is movable to facilitate insertion of the bobbin 68 and removal of the completed coil. However, during the winding operation the upper part 72 of the winding head is maintained in assembled relation with the lower part 70.

The end of the wire 60 is securely held by a clamp 74. The end of the wire 60 is placed between the clamp 74 and :a stationary support 76, and the clamp 74 can conveniently be connected to the rod of a reciprocable piston 78 disposed within a cylinder 80. The piston 78 can be subjected to differential air pressure in opposite directions to clamp and release the end of the wire 60.

A bellcrank 82 having an intermediate pivot 84, has a hooked end 86 located adjacent the winding head. The bellcrank 82 is normally maintained in the position shown in FIGURE 1 by a locking link 88 so that the hooked end 86 is located out of the path of the wire being wound on the bobbin 68. The locking link 88 is attached to a solenoid plunge-r 90 mounted for movement within a solenoid coil 92. When the coil 92 is deenergized, a spring 94 maintains the plunger 90 and the locking lever 88 in the position depicted in FIG- URE 1. When the solenoid coil 92 is energized, the plunger 90 moves to the left, as viewed in FIGURE 1, thereby permitting pivotal movement of the bellcrank 82 by gravity so that the hooked end 86 will be positioned between the winding head and the path of the outer end of the Winding arm as it is rotated thereabout.

With reference to FIGURE 3, the motor can be energized from a source of 60 cycle alternating current through wires 95 and 96. The electrically operated clutch 13 can be energized through wires 97 and 98. A manually ope-rated push button switch 100 is connected in circuit with the clutch 13, the switch 100 being shunted by a switch 102 actuated by a cam 104. The cam 104 is driven by the counter 28. The push button switch 100 is momentarily closed to initiate the winding operation and the switch 102 controlled by the cam 104 automatically deenergizes the clutch 13 after the desired number of turns have been wound on the bobbin 68. The solenoid coil 92 can be energized from the 60 cycle alternating current source through wires 106 and 108 as controlled by a switch 110 actuated by a cam 112. The cam 112 is likewise driven by the counter 28 so as to facilitate closure of the switch 110 as an intermediate turn is being wound on the bobbin. The solenoid coil 92, thereafter, remains energized until the end of the winding cycle, since the switch 110 remains closed.

Referring to FIGURES 1 through 3, the steps involved in winding the unique center tapped coil construction of the present invention are "as follows: A bobbin 68 is placed over the stationary part 70 of the winding head and the movable part 72 of the winding head is thereafter clamped to the stationary part 70. The end of the wire 60 from the previous coil is securely held by the clamp 74. The push button switch 100 is momentarily closed to energize the clutch 13 thereby imparting simultaneous rotary and reciprocating movement to the flyer type winding arm 52. The wire 60 is wound about the core of the bobbin 68 and evenly distributed thereon as shown in FIGURE 2 to form a coil 113. As soon as substantially half of the total number of turns have been wound on the bobbin 68, the cam 112 permits closure of switch 110 thereby energizing the solenoid coil 92. When the solenoid coil 92 is energized, the bellcrank rotates in the clockwise direction by gravity to the full line position shown in FIGURE 2 wherein the hooked end 86 is positioned between the outer end of the winding arm 52 and the winding ahead, as shown in FIGURE 2, so that the wire 60 is wound thereabout. As the wire is wound over the hooked end 86, the wire tension acting on the bellcrank 82 during continued rotation of the winding arm 52 effects counterclockwise rotation of the bellcrank to the phantom position indicated in FIGURE 2. This movement of the bellcrank 82 is sufiicient to withdraw the hooked end 86 out of the path of successive turns of the wire 60 and forms a loop 114 in the intermediate turn 116.

As the hook-ed end 86 of the bellcrank is withdrawn from the full line position of FIGURE 2 to the phantom line position of FIGURE 2, the portion of the intermediate turn 116 adjacent the left hand end of the bobbin is pulled upwardly into engagement with the upper flange 71 of the bobbin. Accordingly, during continued rotation and reciprocation of the Winding arm 52 the withdrawn loop 114 will not interfere with winding of the succeeding turns. In addition, the loop 114 is securely retained in assembled relation with the coil since the remaining half of the turns are wound over the center turn 116.

After the desired total number of turns have been wound about the bobbin 68, the cam 104 actuates the switch 102 to denergize the clutch 13 thereby arresting movement of the winding arm 52. At the same time the cam 112 opens the switch to deenergize the solenoid 92. At this point, the movable part of the winding head 72 is disengaged from the stationary part 70 facilitating removal of the completed coil. At the same time, the clamp 74 is released, and the wire 60 is again positioned between the clamp 74 and the stationary support 76. The wire 60 is then severed, after which the clamp 74 can again be moved into engagement with the stationary support 76 to securely hold the end of the wire 60.

With particular reference to FIGURE 4, when the bobbin 68 having the coil 113 wound thereabout is removed from the winding head, the end leads 118 and 120 of the coil can be twisted together. There-after, one of the wires 118 or 120 can be severed, and the wires 118 and 120 electrically connected by any suitable means, such as welding. The welding operation removes the insulation from the wire. The loop 114 can then be severed to form coil leads 122 and 124 of the center tapped coil. Since ends 122 and 124 are securely held in assembled relation with the bobbin by the outer turns of the coil 113, these wires can support a terminal assembly 126. The terminal assembly 126 includes an insulating housing 128 having a pair of spade terminals 130 and 132 and a pair of terminal lugs 134 and 136. The terminal lugs 134 and 136 are crimped over and welded to the ends of the wires 122 and 124 to produce the finished coil construction shown in FIGURE 5.

From the foregoing it is manifest that the lead wires of the coil constructed according to this invention do not have to be taped in place since the first and last coil turns are mechanically and electrically connected to form the common ground lead for the center tapped coil. In addition, the leads for the .two coil sections are securely held in position by the overlying turns and can conveniently support the terminal assembly. Moreover, by practicing the Welding method of this invention, center tapped coils can be economically manufactured.

While the embodiment of the invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. The method of winding a center tapped coil having a predetermined number of turns on a bobbin from a continuous length of insulated wire, the bobbin having a core with a flange at each end, comprising the steps of, winding substantially half of said predetermined number of turns on said bobbin, extending a hook into the path of movement of said wire to wind one turn near the center about the hook, automatically retracting the hook out of the path of movement of said wire due to wire tension to form a loop by pulling one side of'said one turn into engagement with one of the flanges on said core, and then winding the remainder of said predetermined number of turns on said bobbin over said one turn to securely retain the loop in assembled relation with the coil.

2. The method of withdrawing a loop from an intermediate turn of a coil wound on a bobbin by a flyer type rotary winding arm, comprising the steps of, extending a hook between the bobbin and the path of movement of the winding arm when the arm is winding an intermediate vturn on the bobbin so that a portion of the intermediate turn is wound about the hook, and automatically retracting the hook out of the path of movement of said Winding arm due to wire tension to form a loop on said intermediate turn, so that during completion of the Winding the intermediate turn will be securely held in position by the overlying turns.

2,627,379 2/ 1953 Moore 242-13 References Cited by the Examiner I 2,667,624 1/ 1954 Bels 336-208 XR UNITED STATES PA 2,696,659 12/1954 McCarty 29155.57 721,289 2/1903 Depp et a1- 2,807,369 10/1957 Rlce 29155-57 5 2,889,524 6/1959 Schnntz 336192 972,950 10/1910 Voegtle 336-492 2,904,269 9/1959 Emmger 24211 1,048,205 12/1912 Plke 2906 97s 9/1959 Mikesell 336-192 1,500,181 7/1924 Chapman 29-15557 XR 1,897,604 2/1933 Clemons 29155.56 XR OHN F CAM Primary Examinel.

2,122,894 7/1938 Sager 336192 2 246 143 6/1941 Patton 247 9 10 LAX, WHITMORE A- WILTZ, O. L. RADER, M. 0. 2 404 1 5 7 194 M.ann 336 192 HIRSFIEL W. CHURCH, R. J- CRAWFORD, 2,503,752 4/1950 Mal-chus 29 155.57 XR GERSTMAN R GABLE,

2,624,518 1/1953 Scofield et a1. 24'2 1.1 AssismmEmminm- 

1. THE METHOD OF WINDING A CENTER TAPPED COIL HAVING A PREDETERMINED NUMBER OF TURNS ON A BOBBIN FROM A CONTINUOUS LENGTH OF INSULATED WIRE, THE BOBBIN HAVING A CORE WITH A FLANGE AT EACH END, COMPRISING THE STEPS OF, WINDING SUBSTANTIALLY HALF OF SAID PREDETERMINED NUMBER OF TURNS ON SAID BOBBIN, EXTENDING A HOOK INTO THE PATH OF MOVEMENT OF SAID WIRE TO WIND ONE TURN NEAR THE CENTER ABOUT THE HOOK, AUTOMATICALLY RETRACTING THE HOOK OUT OF THE PATH OF MOVEMENT OF SAID WIRE DUE TO WIRE TENSION TO FORM A LOOP BY PULLING ONE SIDE OF SAID ONE TURN INTO ENGAGEMENT WITH ONE OF THE FLANGES ON SAID CORE, AND THEN WINDING THE REMAINDER OF SAID PREDETERMINED NUMBER OF TURNS ON SAID BOBBIN OVER SAID ONE TURN TO SECURELY RETAIN THE LOOP IN ASSEMBLED RELATION WITH THE COIL. 